IMPLANTABLE ARTICLE, METHOD OF FORMING SAME AND METHOD FOR REDUCING THROMBOGENICITY

• US 20070299510A1
• Filed: 05/25/2007
• Published: 12/27/2007
• Est. Priority Date: 06/15/2004
• Status: Active Grant

• Current Assignee: Nanyang Technology University
• Original Assignee: Nanyang Technology University
• Inventors: VENKATRAMAN, Subramanian, BOEY, Yin
• Granted Patent: US 8,999,364 B2
• Time in Patent Office: Days
• US Class Current: 623/1.44
• CPC Class Codes: A61F 2/0077 Special surfaces of prostheses, e.g. for improving ingrowth A61F2/30767 takes precedence
• CPC Class Codes: A61F 2/06 Blood vessels
• CPC Class Codes: A61F 2210/0004 bioabsorbable
• CPC Class Codes: A61L 2400/18 Modification of implant surfaces in order to improve biocompatibility, cell growth, fixation of biomolecules, e.g. plasma treatment
• CPC Class Codes: A61L 2420/06 Coatings containing a mixture of two or more compounds
• CPC Class Codes: A61L 2420/08 Coatings comprising two or more layers
• CPC Class Codes: A61L 27/18 obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
• CPC Class Codes: A61L 27/34 Macromolecular materials
• CPC Class Codes: A61L 27/50 Materials characterised by their function or physical properties , e.g. injectable or lubricating compositions, shape-memory materials, surface modified materials
• CPC Class Codes: A61L 27/56 Porous materials, e.g. foams or sponges
• CPC Class Codes: A61L 27/58 Materials at least partially resorbable by the body
• CPC Class Codes: A61L 29/08 Materials for coatings
• CPC Class Codes: A61L 31/08 Materials for coatings
• CPC Class Codes: A61L 31/10 Macromolecular materials
• CPC Class Codes: A61L 33/0011 Anticoagulant, e.g. heparin, platelet aggregation inhibitor, fibrinolytic agent, other than enzymes, attached to the substrate
• CPC Class Codes: C08L 67/04 Polyesters derived from hydroxycarboxylic acids, e.g. lactones C08L67/06 takes precedence

Abstract

Endothelialization of a bodily fluid or tissue-contacting, particularly blood-contacting, surface may be accomplished to render that surface substantially non-thrombogenic. Thrombosis may also be mitigated or eliminated by providing an eroding layer on the surface that results in the removal of any thrombus formation as the layer erodes. An implantable device may utilize at least one surface having a plurality of nano-craters thereon that enhance or promote endothelialization. Additionally, an implantable device may have at least one first degradable layer for contacting bodily fluid or tissue and disposed about a central core, and at least one second degradable layer between the first degradable layer and the central core. The first degradable layer has a first degradation rate and the second degradable layer has a second degradation rate which degrades more slowly than the first degradable layer on contact with bodily fluid or tissue.

Claims

1. An implantable device comprising:

at least one first degradable layer providing at least one surface of the implantable device for contacting bodily fluid or tissue and disposed about a central core; and

at least one second degradable layer between said first degradable layer and the central core, wherein said first degradable layer has a first degradation rate and said second degradable layer has a second degradation rate such that said at least one first degradable layer degrades more rapidly then said at least one second degradable layer on contact with bodily fluid or tissue.

2. The implantable device of claim 1, wherein the first degradable layer comprises a different material than the second degradable layer.

3. The implantable device of claim 1, wherein the second degradable layer comprises PLA and the first degradable layer comprises PLGA.

4. The implantable device of claim 1, wherein the first degradable layer comprises a polymer selected from the group consisting of PLGA 80/20, PLGA 75/25, and PLGA 53/47.

5. The implantable device of claim 1, further comprising:

at least one third degradable layer between the at least one second degradable layer and the central core and having a third degradation rate slower than the second degradation rate; and

at least one fourth degradable layer between the at least one third degradable layer and the central core and having a fourth degradation rate slower than the third degradation rate.

6. The implantable device of claim 5, wherein the first degradable layer comprises PLGA 53/47, the second degradable layer comprises PLGA 75/25, the third degradable layer comprises PLGA 80/20, and the fourth degradable layer comprises PLA.

7. The implantable device of claim 1, wherein the implantable device is selected from the group consisting of a stent, a graft, a conduit, and a valve or dialysis tubing.

8. A method of reducing thrombogenicity of an implantable device having at least one surface for contacting bodily fluid or tissue, comprising:

providing at least one first degradable layer which provides said at least one surface and which is disposed about a central core, and at least one second degradable layer between said first degradable layer and the central core,

wherein said first degradable layer has a first degradation rate and said second degradable layer has a second degradation rate such that said at least one first degradable layer degrades more rapidly than said at least one second degradable layer on contact with bodily fluid or tissue.

9. The method of claim 8, wherein the implantable device is selected from the group consisting of a stent, a graft, a conduit, a valve, and dialysis tubing.

10. The method of claim 8, wherein providing comprises providing the first degradable layer having a different material than the second degradable layer.

11. The method of claim 8, wherein providing comprises providing the first degradable layer made from a polymer selected from the group consisting of PGA, PLA and PGLA.

12. The method of claim 8, wherein providing comprises providing the first degradable layer made from PLA and the second degradable layer made from PLGA.

13. The method of claim 8, wherein providing comprises providing the second material made from a polymer selected from the group consisting of PLGA 80/20, PLGA 75/25, and PLGA 53/47.

14. The method of claim 8, wherein the device further comprises:

at least one third degradable layer between the at least one second degradable layer and the central core and having a third degradation rate slower than the second degradation rate; and

at least one fourth degradable layer between the at least one third degradable layer and the central core and having a fourth degradation rate slower than the third degradation rate.

15. The method of claim 14, wherein the first degradable layer comprises PLDA 53/47, the second degradable layer comprises PLGA 75/25, the third degradable layer comprises PLGA 80/20 and the fourth degradable layer comprises PLA.